<html>
<head>
<style>
.normal
{
height:auto;
}
.big
{
height:200px;
}
.ex
{
height:500px;
width:100px;
}
</style>
</head>

<body>
<p class="ex">The height of this paragraph is 100px.</p>
<p class="big">This is some text in a paragraph. This is some text in a paragraph.
This is some text in a paragraph. This is some text in a paragraph.
This is some text in a paragraph. This is some text in a paragraph.</p>
<p>Text</p>
</body>
</html>